In this contract, the team will construct novel common aperture hybrid free space optical (FSO)/RF communication transceivers mounted on high performance gimbal stages. These will allow the pointing, acquisition, and tracking of directional beam wireless links operating in a physically secure manner at high data rates. Prototype FSO/RF transceivers are called CHORD (Common Aperture Optical RF Data links), and one is shown schematically in the figure to the right.

The transceiver has two large apertures, shown in red, one of which is the FSO/RF receiver sharing a common aperture, while the other is the RF transmitter. The laser transmitter (yellow) is co-directed with the RF transmitted beam. The optical receiver channel incorporates a non-imaging concentrator to provide alignment robustness and a relatively large field of view. The whole assembly is mounted on a gimbal driven by high torque “pancake” motors. Current technology should allow these hybrid transceivers to operate at data rates at least up to 1.25Gb/s and penetrate rain, clouds, and fog because of their dual laser/RF capabilities.